Linked Questions

13
votes
2answers
44k views

Is WGS84 a Coordinate system or projection system? [duplicate]

WGS84 is often referred to as a "projection system" and sometimes it is confusing to me about what a "projection system" is and where WGS84 falls in one. Could someone please clear that up for me?
2
votes
2answers
401 views

What is the difference between a datum and an ellipsoid? [duplicate]

For example I am converting from ECEF to lla using def ecef_to_lla(x, y, z): lla = pyproj.Proj(proj='latlong', ellps='WGS84', datum='WGS84') ecef = pyproj.Proj(proj='geocent', ellps='WGS84', ...
1
vote
0answers
117 views

Are ellipsoid and datum the same? [duplicate]

Are the datum and the ellipsoid the same? What is a Datum? The Earth is shaped like a flattened sphere. This shape is called an ellipsoid. A datum is a model of the earth that is used in mapping. ...
1
vote
0answers
93 views

Geographic coordinate system and datum [duplicate]

I am bit confused about datums used to define a localised coordinate system for a specific area. Definitions say that, datum defines how a certain well-established point (i.e., reference point) on ...
0
votes
0answers
76 views

what is the difference between the Geographic coordinate, transformed coordinate and screen coordinate [duplicate]

What is the difference between the Geographic coordinate, transformed coordinate(projected) ,cartesian coordinate, and screen coordinate? Is there a live example? And what is the association between ...
25
votes
7answers
3k views

Spatial reference for dummies?

Can anyone recommend a good reference or tutorial that explains the principles of spatial references, projections, and coordinate systems? We are a small team of programmers working with GIS ...
15
votes
5answers
20k views

What is projection of WGS84 in GIS software? [duplicate]

WGS84 is a reference ellipsoid that determines coordinates of every point on Earth using latitude, longitude and height about the its surface. This ellipsoid is often used as a base to make maps. ...
14
votes
1answer
35k views

Understanding difference between Coordinate System and Projection?

Can somebody please explain what is the difference between the Coordinate system (WGS 84 for example) and a Projection (Universal Transverse Mercator for example)? What is the difference between a ...
0
votes
2answers
2k views

How would I convert this point to WKID 4326?

This is a point in Brewster, MA, USA. How would it be converted to WKID 4326? 324299.3348436486, 832511.5939650714
1
vote
1answer
2k views

Difference between WGS_1984_UTM_33N and GCS_WGS_84

What is the difference between: a map that has a projected coordinate system of WGS_1984_UTM_33N, a geographic coordinate system of GCS_WGS_1984, and a datum of D_WGS_1984 a map that has no projected ...
1
vote
1answer
1k views

Latitude, longitude, projections, CRS

I'm confused about the following basic points: Do lat/long points have a projection or are they projection agnostic? Do these points live in a sphere or a plane? I understand that projections are ...
4
votes
1answer
576 views

No difference between distances measured in projected and non-projected data

I'm performing measurements of distances in Km between a lot of localities by using the "Point Distance" in ArcGis 9.3. I realized that the results obtained after using projected coordinate system are ...
3
votes
1answer
1k views

Which BC Albers should I use and is there any difference?

I was about to calculate the area of some polygons and before I did I did some research. I found that the area of the polygon will be represented in the units of the projection used. So I did some ...
5
votes
1answer
368 views

Vertical Datum and Projection

Does vertical datum get projected? I feel a bit confused with the concept of the vertical datum and doing a projection.
1
vote
2answers
613 views

Advanced Digitizing Panel Not Enabled When Map View is in Geographic Coordinates

I am trying to use the advanced digitizing panel with a new line geometry layer. I am using QGIS 3.0.3 The QGIS documentation states: "The tools are not enabled if the map view is in geographic ...

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